On Apr 18, 5:32 pm, Daishy <dai...@web.de> wrote: > Hi together, > > I'm trying to use select_related in a query, but it seems i'm doing > something wrong. I have googled, but not really found anything (Maybee > used the wrong keywords :/) > > I've got a model that is related to another model, roughly like that: > > class A(models.Model): > a = models.CharField() > > class B(models.Model): > link = models.ForeignKey(A) > > Now i want to query all entries in B along with the related models, > which would be the following (?) > objs = B.objects.select_related().all() > item = objs[0] > > This produces one correct join-statement and populates all objects. > Now my problem: I need the keys of B / link.pk. Unfortunately item.pk, > item.id, item.link.pk, item.link.id gives me None as result. Do i need > to specify some other options, or is that just the default behaviour? > If so, is there a way to fill the ids anyhow? (I've got 30 rows with > ~2 foreign-keys each and all of them get displayed, which hits the db > quite often.) > I'm using Django from the trunk. > > Thanks for any help! > Daishy >
I'm really not sure what you're asking here. If you execute the code you've given and then print item.id or item.pk, that will give you the primary key of the B object that you got originally. If you print item.link.id, that will give you the primary key of the A object that is related to the B object you have. You don't need any extra code to do this. (In fact, if you only need the primary key of the related A object, you don't even need to do select_related - you can just do item.link_id, as this is an attribute of the B model not the A one. But presumably you're after more attributes than just the pk.) -- DR. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
